The process of manufacturing certain micro-devices such as semiconductor integrated circuits (ICs), liquid crystal displays, micro-electro-mechanical devices (MEMs), digital mirror devices (DMDs), silicon-strip detectors and like involves the use of high-resolution lithography systems. Recently, there has been increased emphasis on digital lithography systems that rely on digital imaging systems to meet the increasing demands on achieving greater resolution and greater flexibility. A digital imaging system does not rely on the use of a mask but instead relies on an image transducer or spatial light modulator, such as a DMD, to define the image. For these reasons, the technology is referred to as “maskless digital lithography.”
Digital imaging systems are inherently slower that their step-and-scan and step-and repeat counterparts because their field sizes are much smaller and the image transducer is stationary. In an effort to compensate for this disadvantage, such systems are operated so that the exposure time for a single frame is very short and the number of frames containing repeating parts of the pattern is large.
It would be advantageous to lengthen the maximum single frame exposure time and reduce the number of frames requiring the same parts of the pattern. This would result in a more efficient use of the illumination light and a higher throughput.